My rhino 4 does not center

[Sayyaaf]

I bought a rhino multiplex servo for my FG baja steering, I tried running it and it always seem to take right more than left, I know trimming could solve the problem but I like my servo's centered with 0 trim, is that a common problem with Rhino's ? I had FG RTR which didn't have that problem, but the rhino when at 0 trim, the servo horn either mound one tooth right or left, can't be centered. Is this fixable or shall I go trimming only ?

I had to check my turnbuckles length and they were exact length, so it must be the servo no other possibilities ...

 

[sperera]

sorry mate but I don't understand the problem. when you installed the servo i assumed you had your epa's and centre set to 0 trim, so when you turn left or right it wont go back to centre? if thats the case i think there's a servo problem, if your trim it back to centre and turn the steering either way you will come with same problm, can you confirm?

 

[Sayyaaf]

Nop , that is not the problem, I mean installing the servo horn, it will always install either right biased or left biasd, does not install in the middle, I don't know how to explain it ...

Ok I found this on the web,

this is the perfect position for the horn right ?

I can't install it like that without trimming, it will be either going more left or right.

 

[Unknown460]

Mine was the same when i installed it, and had to correct it with trim

I think the main reason is due to the rhino's having such a coarse spline, showing much more mis alignment than most servo's would and therefore less adjustment of horn fixing position.

maybe wrong though?

 

[aaean]

the horns do sit a little off, but depends on the horn you are using. if you have a high end handset you can normally ajust the center point left or right a little (its not like ajusting the trim its another setting)

 

[atom3624]

It's the splines.
I think mine were the same, so you trim it to the correct centre, but obviously get it as close as you can on Zero beforehand.
Al.

 

[Trip]

Mine was the same on my Hitec servo (same co as Multiplex) it was off to the left or right... Correct it with the trim on your radio or adjust the tie rods... I would just trim it though.

 

[Bigger the Better]

The top spline gear is a separate gear from what I remember. You could try moving the spline gear over one gear tooth inside to try centering it. It would take disassembling it to do that.

 

[pipeous]

The hitec 805 is the same. the pitch of the gear is quite steep and you need more choices. I installed dual 805's in the cen and used servo horns with multiple sides. ceneterd the servo then went around the sides to find the one that sat 90 degrees (why I marked the arrows)

 

[pipeous]

in helis, it was common practice to use the round servo horns with zero holes. then you could just drill the hole where you needed so it was exact. a heli setup is crucial for proper angles

 

[Timmahh]

becuz of the large 8mm drive horn, when you set the horn on, you ll nearly never have it go on just right. use your Sub Trim on the steering channel to adjust to center. using subtrim keeps the same amount of turn radius in each direction of center. when you use the TRIM to adjust center, you make one side have less available travel, while the other side will have more available travel. no biggie, if you have the right setup, but on some rights, it can limit turn radius in one dirction.

 

[sperera]

i don't mean to be rude but I don't think this matters.

to explain when you install the horn it might sit slightley to the left but your going to adjust your EPA anyway so its going to move from that position.

if by some miracle your epa's are perfect by the horn sitting exactly straight, and its not centre with trim 0 then just adjust the trim.

every one of my servo's didnt fit from new dead centre but was moved anyway to ensure EPA is correct.

 

[Trip]

Your epa should be independent from your trims...

I think the servo horn being off center bothered him. I went through the same thing when I built my first FG. It's just the nature of the FG beast.

 

[Sayyaaf]

actually FG RTR servo didn't have that problem.

So if re build the servo I might be able to shift it one tooth so it might allign ? what about metal servo horns, does that address that issue ?

 

[marksp]

That's what sub-trim is for.

 

[Sayyaaf]

The only trim value that make it line up is 50+ , this is not normal.

 

[Trip]

Then it sounds like the steering rods are way off. Is one bent maybe? They are adjustable so if one is longer than the other, just adjust it out.

I forgot to center my servo before I threadlocked the servo horn. Luckily my Airtronics radio would allow me to turn the trim all the way to the right to center the servo and then I called that "Zero" then I could adjust the steering trim and sub trims from there...

Once the servo is mounted you won't see the servo horn if it's off a few degrees...

It would be easier on us if you could snap a few pictures of the problem. Snap a few of the Camber too.

 

[Bigger the Better]

Did you try to move the servo horn gear one tooth over? If you cannot make the servos center match the servo horn like in the picture you show, then the gearing may be a tooth off for the servo horn you are using.
Just a thought.

 

[atom3624]

There's no way you should require 50+ to centre the servo horn.
Try resetting to '0', keep the electronics powered, remove the horn and centre to closest possible, and then re-trim electronically.

Al.

 

[pipeous]

yup trim and sub trims need to be zero (on the radio near the wheel and in the menu)